Poster: Temperature Responses

Abs # 190: Tomato pathogenesis related protein 1b1 (PrP1b1): specific induction upon chilling and sustained accumulation in transgenic fruit expressing yeast S-adenosylmethionine decarboxylase

Presenter:	Goyal, Ravinder , goyalr@ba.ars.usda.gov
Authors	Goyal, Ravinder  (A) (B)  Bernadac, Anne  (C)   Ali, Nasreen  (A) (B)  Handa, Avtar K (D)   Mattoo,  Autar K (A)
Affiliations:	(A): United States Department of Agriculture (B): University of Maryland (C): Ensat at Tolouse (D): Purdue University

Plants combat stress through an array of mechanisms involving defense-related proteins and other metabolites. Many of these mechanisms likely involve gene transcription and posttranscriptional regulation. Among the metabolites implicated in providing protection against abiotic stresses is a class of ubiquitous organic aliphatic cations, polyamines. For instance, in vitro studies have suggested that polyamines alleviate chilling injury. The mechanism of polyamines-mediated protection against damage due to chilling injury is unknown. We have approached this subject by studying two transgenic tomato lines that express yeast S-adenosylmethionine decarboxylase in a fruit-specific manner and which accumulate higher polyamines, spermidine and spermine, but not putrescine (Nature Biotechnol. 20, 613-618, 2002). Our studies have identified pathogenesis related protein 1b1 (PrP1b1) as a major protein that is transiently induced when tomato fruit are chilled and then rewarmed. The transcripts of the PrP1b1 gene also show transient accumulation under these conditions. However, in the high polyamines-accumulating transgenic fruits, the induction of PrP1b1 transcript and protein levels was several-fold higher than the non-transgenic fruit. The accumulated PrP1b1 protein has a longer half-life in the transgenic fruits. Further, we have assessed if polyamines cross talk with ethylene and jasmonic acid signal transduction pathways to regulate the gene expression of PrP1b1.